High security electrical key

ABSTRACT

A key for use with an electrical security system includes a plurality of contacts for conveying a binary coded permutation of electric signals to key receiving means of the system for actuating the system when the key is the proper key, a plurality of conductor paths for interconnecting at least a portion of the plurality of contacts, and control means associated with the conductor paths for controlling the conductivity therethrough. The control means has a first condition when the key is engaged with the key receiving means and second condition when the contacts are disengaged from the key receiving means. When the control means is in its first condition the contacts convey the predetermined binary coded permutation to the key receiving means so as to actuate the security system and when the control means is in its second condition the contacts are inoperable to convey the predetermined code stored on the key. Accordingly, deciphering of the key by an unauthorized person is prevented when the key is disengaged from the key receiving means and the control means is in its second condition.

United States Patent Hedin et a1.

[451 Mar.21,l972

[54] HIGH SECURITY ELECTRICAL KEY Robert A. l-ledin, Yorba Linda; Robert11. Du Quesnay, Buena Park, both of Calif.

[73] Assignee: Eaton Yale & Towne Inc., Cleveland, Ohio [22] Filed: Feb.22, 1971 [21] Appl. No.: 117,271

[72] Inventors:

Primary Examiner-Donald J. Yusko Attorney-Teagno & Toddy [57] ABSTRACT Akey for use with an electrical security system includes a plurality ofcontacts for conveying a binary coded permutation of electric signals tokey receiving means of the system for actuating the system when the keyis the proper key, a plurality of conductor paths for interconnecting atleast a portion of the plurality of contacts, and control meansassociated with the conductor paths for controlling the conductivitytherethrough. The control means has a first condition when the key isengaged with the key receiving means and second condition when thecontacts are disengagedfrom the key receiving means. When the controlmeans is in its first condition the contacts convey the predeterminedbinary coded permutation to the key receiving means so as to actuate thesecurity system and when the control means is in its second conditionthe contacts are inoperable to convey the predetermined code stored onthe key. Accordingly, deciphering of the key by an unauthorized personis prevented when the key is disengaged from the key receiving means andthe control means is in its second condition.

17 Claims, 2 Drawing Figures l l O O l 0 0 I60 180 20G 226 24G 260 280306 320 I I l I I I l f POWER KEY RECEIVING MEANS UPPLY COD ED CIRCUITSI 66 34 "F CONTROLLED LOCK PATENTEDMARZI I972 'l' 6 'o' l 4d I60 I80 20022G 240 260 28C! 306 l?2d r l l// l/ r! I l o I o o 0 POWER I KEYRECEIVING MEANS & SUPPLY CODED CIRCUITS INVENTORS R. A. HEDl/V R. H.DUOUES/VAY ATTORNEYS HIGH SECURITY ELECTRICAL KEY The present inventionrelates to a key for controlling electric locks and security systems,and more specifically to a key having binary coded information storedthereon and means for preventing deciphering of the coded informationstored on the key.

Keys that utilize open and closed electrical circuits to convey a binarycoded permutation to a lock or security system are known in the art. Onesuch key is disclosed in the I-ledin and Balzano US. Pat. Re..No.27,013, issued Dec. 22, I970. The Hedin and Balzano patent discloses akey having a plurality of contact members engageable with contacts of alock or security system. Certain of the contact members are in a closedcircuit and others are in an open circuit so that a binary code may beapplied to the lock system to effect actuation thereof. Another knownkey utilizing a binary coded permutation to operate a security system isdisclosed in the Hedin application entitled Keys for Electronic SecurityApparatus,"

- Ser. No. 23,272, Filed Mar. 27, 1970, which discloses a key 7 that issatisfactory for many purposes, it is possible to utilize proceduresthat will decipher the keys and there is need for a key that will offerthe best security.

Accordingly, an object of the present invention is to provide a new andimproved key for actuating a security system which has means therein toprevent the deciphering of the code stored on the key.

Another object of the present invention is to provide a new and improvedkey for actuating a security system which has key receiving means, thekey including a plurality of contacts, a plurality of conductor pathsinterconnecting at least a portion of the plurality of contacts andmeans located in the plurality of conductor paths for controlling theconductivity of the paths, and wherein the means for controlling theconductivity'has a first condition which enables the contacts to conveybinary coded permutation to the key receiving means and a secondcondition in which the contacts are inoperable to convey the binarycoded permutation.

Still another object of the present invention is to provide a new andimproved key for actuating a security system, the key having a pluralityof contacts some of which receive information from the key and at leastone of which is a power contact for applying power to the key, the keyincluding a plurality of key contacts for conveying information to thecontacts of the security system, a power receiving contact engageablewith the power contact of the security system and through which powerwill be directed to at least one of the plurality of key contacts, andmeans interconnecting at least a portion of the plurality of keycontacts and having a first condition when said key contacts engage withthe plurality of contacts of the security system, the power receivingcontact then engaging with the power contact, to interconnect the keycontacts in a predetermined manner to enable the key contact to direct apredetermined code to the contacts of the security system, and a secondcondition effective when the key contacts are disengaged from theplurality of contacts of the security system to prevent the key contactsfrom conveying the predetermined code.

A further object of the present invention is to provide a new andimproved key for actuating a security system having key receiving means,including a plurality of contacts for conveying a predetermined binarycoded permutation to the key receiving means to actuate the securitysystem, a pluralityof conductor paths interconnecting at least a portionof the plurality of contacts, and control means having a first conditionenabling the contacts to convey the predetermined binary codedpermutation to the key receiving means and a second condition disguisingthe predetermined binary coded permutation when the contacts are notengaged with the key receiving means, and wherein the control means whenin its second condition enables the contacts to convey a plurality ofbinary coded permutations to thereby prevent deciphering of saidpredetermined binary coded permutation.

Further objects and advantages of the present invention will becomeapparent from the following detailed description thereof taken inconjunction with the following drawings wherein:

FIG. I is a perspective view of a key embodying the present invention;and

FIG. 2 illustrates schematically the circuitry of the key and thesecurity system.

A binary coded key 10 having a body member 12 and a plurality ofcontacts 14, l6, I8, 20, 22, 24, 26, 28, 30, and 32 is illustrated inFIG. 1 and 2. The key I0 is operable to be engaged with a key receivingmeans of a security system which controls access to a secured area. Thesecurity system is schematically illustrated as including key receivingmeans and coded circuit 34 and a lock 36 which is controlled bythe-circuitry 34. The key receiving means and coded circuits may be in apreferred embodiment similar to the circuitry disclosed in the I-Iedinand Balzano patent already referred to U.S. Pat. Re. No. 27,013 entitledKey Actuated Electronic Security System," issued Dec. 22, 1970. As isdescribed in the Hedin and Balzano patent the key receiving means isoperable to receive information stored onthe key 10 upon engagementtherewith. The key receiving means directs the information to the codedcircuits and if the information directed to the coded circuits iscorrect, i.e., a correct code, the coded circuits effect operation ofthe lock 36 to provide for access to the secured area.

The key receiving means includes a plurality of contacts 14a, 16a, 18a,20a, 22a, 24a, 26a, 28a, 30a, and 32a which are operable to engage withthe contacts 14-32 respectively of the key 10 upon insertion of the key10 into the key receiving means. The key 10 will then be operable toconvey a binary code via the key receiving means to the code circuitry.If the binary code is a proper code the controlled lock 36 will beactuated and entry to the secured area may be effected as is describedin the aforementioned patent. A particular code is assumed simply forthe purpose of describing the invention, and that code is indicated inFIG. 2 by a group of 0" and l information bits C contained in the codedcircuits 34, and by corresponding bits CK contained in the key.

The contacts 14-30 disposed on the body 12 of the key 10 are operable toform either closed or open circuits with the contact 32 which is a powercontact. The contact 32 is operable to be engaged with the contact 32aof the key receiving means which is associated with a power supply,schematically illustrated in FIG. 2, to thereby apply power to thecontact 32 upon insertion of the key 10 into the key receiving means. Ifa closed circuit is completed between the contact 32 and one of theother contacts, a potential will be applied to the one contact and thecontact will convey to the key receiving means a 1 bit of information.If an open circuit is formed between the contact 32 and one of the othercontacts, the one contact will convey a 0 bit of information to the keyreceiving means. As is schematically illustrated in FIG. 2 the contacts14-30 form open and closed circuits with the contact 32 to conveyinformation in the form of binary bits to the coded circuits and keyreceiving means 34. The contacts 14, 18, 20, 22 and 28 are operable inthe present embodiment of the invention to convey 1 bits of informationto the key receiving means and coded circuits 34. The 0 and 1 bits ofinformation form a binary coded permutation which is utilized to actuatethe lock 36. It should be appreciated that while specific bits ofinformation are illustrated associated with specific contacts these maybe easily varied to form a variety of codes.

In the form that has been chosen to illustrate, the key contacts 18, 22,28 and 30 merely utilize an earlier development shown in the applicationof R. A. I-Iedin, Ser. No. 27,686, filed Apr. 13, I970, entitled Methodand Apparatus for Producing Encoded Electrical Keys. Thus, when the keyis engaged in the key receiving means, power will be transmitted via thecontact 32 to a bus bar 40 located on the upper portion of the bodymember 12. The bus bar 40 will then apply a potential directly to thecontacts 18, 22, and 28 via the conductive por tions 42, 44 and 46disposed between the bus bar 40 and the contacts 18, 22, and 28,respectively. Thus, the contacts 18, 22 and 28 will convey 1 bits ofinformation to the key receiving means via the conductive portionsdisposed between the bus bar 40 and the contacts. The contact 30 mayhave been formed with a conductive portion connecting it with bus bar40, but that portion has been removed and therefore no potential will beapplied thereto and thus the contact 30 will convey a 0 bit ofinformation to the key receiving means. By utilizing the earlier Hedindevelopment mentioned above, the owner of the key may remove any of theconductive portions 42, 44, 46 so as to make limited changes in thecode, enabling him to establish a code that is unknown to themanufacturer of the key.

Supplying power to the power contact 32 also effects energization ofcontrol means 38 disposed in the upper portion of the key body 12. Thecontrol means 38 is associated with circuitry which provides conductorpaths between certain of the contacts so that either 0 or 1 bits ofinformation can be conveyed by the contacts associated with the controlmeans 38. The control means 38 is energized via the line 48 which isconnected to the upper portion of the contact 32. Energization of thecontrol means 38 will enable the contacts 14 and 20 to convey 1 bits ofinformation to the key receiving means and the contacts 16, 24 and 26 toconvey 0 bits of information to the key receiving means.

The control circuitry 38 includes a PNP transistor 50, and a pair of NPNtransistors 52 and 54. A resistor 56 is connected to the base of thetransistor 50, and resistors 58 and 60 are connected to the bases of thetransistors 52 and 54 respectively. The potential applied to the line 48will bias the base of transistor 52 through the resistor 58 and the baseof the transistor 54 through a line 62 and the resistor 60. Thepotential on line 48 will also be applied through the conductor 62 tothe emitter of the transistor 50. The base of the transistor 50 isconnected through the resistor 56 and a lead 64 to contact 16. Whencontact 16 engages with the contact 16a of the key receiving means,there will be a difference of potential in effect grounding the base oftransistor 50, as represented schematically by ground 66 connected tocontact 16a of the key receiving means. Since the base of transistor 50is grounded and a positive potential is applied to the emitter thereofthrough the line 48 and the line 62, the transistor 50 will conduct.

Conduction of transistor 50 will complete a circuit between the emitterand collector thereof to apply a potential through a line 70 to the lead68. The lead 68 is connected to the contact 14 and thus a potential willbe applied to the contact 14 which will enable the contact 14 to conveya 1 bit to the contact 14a of the key receiving means. The contact 16will convey a 0 bit of information to the contact 16a of the keyreceiving means. It should be appreciated that while a small potentialmight be applied to the contacts 16 and 16a due to grounding of the baseof transistor 50, the potential will not be great enough to effect theconveyance of a 1 bit of information to the key receiving means.

Conduction of the transistor 50 will also enable a positive potential tobe applied along the line 70 which is connected to the collector oftransistor 52. Since at this time a potential is applied to the base ofthe transistor 52 through the resistor 58 from the line 48, thetransistor 52 will conduct and complete a circuit through the collectoremitter thereof to line 72. The line 72 is connected to a lead 74 whichis connected to the contact 20 and the potential on line 72 will then beapplied through lead 74 to the contact 20. The potential applied to thecontact 20 will enable the contact 20 to apply a 1 bit of information tothe contact 20a of the key receiving means.

The application of power to the line 48 effects the biasing of the baseof transistor 54 through the resistor 60. However, since no potential isapplied to the collector of the transistor the transistor 54 will remainin an ofi condition and the leads 76 and 78 which are connected to thecollector and emitter thereof respectively will not have a potentialapplied there along. The leads 76 and 78 are respectively connected tothe contacts 26 and 24 of the key 10 and thus a 0 bit of informationwill be conveyed by the contacts 24 and 36.

The purpose of transistor 54 will be better understood if at this pointa different condition is assumed. Thus, assume that, by some means suchas a testing instrument, a potential is applied directly to the contact26 of the key 10. The application of a potential to the contact 26 wouldeffect a potential along the line 76 to the collector of transistor 54.if at this time the base of the transistor 54 is biased by potential online 48, the potential which is applied to the collector would turntransistor 54 on and power would flow through the collector emittercircuit thereof to the line 78 to apply a potential to the contact 24.in the assumed condition, where a potential is applied directly to thecontact 26a the contact 24 will indicate a 1 bit of information. Thatnaturally departs from the predetermined code of the key and thereforeindicates indicates false code.

It should be appreciated that when a potential is applied to key contact26, as when the key is in position engaging the key receiving means, thetransistor 54 will conduct and the key 10 will convey a binary codedpermutation which has a 1 bit of information at the contact 24. Ifhowever, a zero potential is applied to the contact 26 the transistor 54will not conduct when the key engages the key receiving means andaccordingly a 0 bit of information will be conveyed by the contact 24.Thus, it should be apparent that the binary coded permutation that willbe conveyed by the key will depend upon the potential applied or notapplied to the contact 26. This enables the key to convey a plurality ofbinary coded permutations. Since the key will convey its proper binarycoded permutation only when a potential is applied to a certain keycontact or contacts, in this example including the contact 26, theproper permutation will be disguised when the key is removed from thekey receiving means.

At this point, attention may be called to the fact that the key can beutilized to offer a second code permutation that may be desired. Thus,in the circuitry described, the contact 24 can offer either a l or a 0bit of information. Therefore, depending upon the predetermined binarycoded permutation needed to actuate the security system, a potential mayor may not be applied to the contact 26 and the transistor 54 may or maynot be utilized to direct a 1 bit of information to the contact 24.

When the key 10 is engaged with the key receiving means the binary codedpermutation is applied to the key receiving means via the contacts 14-30of the key 10. The binary coded information, which consists of the 1bits of information applied by the contacts 14, 18, 20, 22, and 28 andthe 0 bits of information which are applied by the contacts 16, 24, 26,and 30, is controlled by the presence or absence of conductive portionsbetween the bus bar 40 and the contacts 14 to 30, the operation of thecontrol means 38, and the electrical condition of the key receivingmeans contacts 14a to 32a. It should be apparent from all of theforegoing that the control means has a first condition when the key 10is engaged with the key receiving means and the contacts 14 to 32 engagethe contacts 14a to 32a and a second condition when the key is notengaged with the key receiving means. The second condition of thecontrol means is such as to effectively prevent deciphering of the codestored on the key 10 when the key is not engaged with the key receivingmeans. Moreover, the body 12 of the key is preferably made of a materialwhich prevents X-ray of the key, and which also renders the circuitrydestroyed if the key is taken apart. Thus, if the key 10 falls into thehands of an unauthorized person, he cannot duplicate the code stored onthe key without destroying the key.

There are three general types of testing that might be attempted todetermine the binary coded permutation of the key. Perhaps the mostobvious test would be to use a battery and a light to test theconductivity of the different terminals by engaging the contacts of thebattery and light with different contacts of the key. A test such asthis applied to the key would show that the terminals 18, 22, 28 and 32are closed circuits. A person using this test would have no way ofknowing that the contacts 14, 20 are also closed circuits. Thus,deciphering of the code by this method would not be producme.

A more sophisticated test would be to use an ohmmeter and measure theresistance of all the terminals. In this type of test it should beappreciated that the resistances of the terminals 14, 16, 20, 24, 26 and32 would all be about the same due to their connection with the controlmeans 38. Therefore, the distinction between these terminals could notbe found by using an ohmmeter. In a further attempt to decipher the key,power might be applied to one of the terminals and the output of thedifferent terminals measured. However, it should be apparent that ifpower were applied to the terminal 32 it would be necessary to groundterminal 16in order for the code to be deciphered thereon sincetransistor 50 will not conduct unless there is a certain potentialthrough terminal 16. Thus, unless it is known specifically whatterminals to ground and what terminals to apply power to, it will beexceedingly difficult or impossible to decipher the key. Moreover, sinceit is also possible to apply power to more than one of the leads, i.e.,such as the lead 26 to bias transistor 54 into condition to therebyobtain from the key a different code in which the contact 24 wouldconvey a 1 bit of information, it would be impossible for anunauthorized person to known exactly which of the codes he might findwould be the correct code.

it should be appreciated that while only terminals have been shown inconjunction with the key, more or less terminals could be utilizeddepending upon the degree of security and the number of possiblecombinations desired to be utilized with the key. For example, aplurality of contacts such as the contacts l4-32 naturally may bedisposed on the opposite side of the key in a parallel relation to thecontacts 14 to 32 shown in FIG. 1. This of course would substantiallyincrease the number of code changes which could be stored on a keythereby adding to the complexity of deciphering of the key. Moreover,the complexity of the control means can be varied to connect more orless contacts to it as the security is desired to be increased ordecreased respectively. It should be realized that the control meansillustrated is for a particular key and, using that key as an example,persons who are skilled in the art will be able to vary the controlmeans to enable different codes to be stored on the key 10.

From the foregoing it should be apparent that a new and improved key foractuating a security system has been provided. The key includes aplurality of contacts receiving power from the security system and inreturn conveying information to the security system. interconnecting atleast a portion of the plurality of contacts is a control means which isoperable, when the contacts of the key engage contacts of a keyreceiving means of a security system to effect the application of apredetermined code from the key to the key receiving means of thesecurity system. When the key is removed from the security system thecontrol means takes another condition which is different from thecondition of the control means when the key engages with the keyreceiving means of the security system. The second condition of thecontrol means is such as to effectively prevent deciphering of thepredetermined code stored on the key by an unauthorized person.

While the key of the present invention has been described in relation toa security system that comprises a lock mechanism, it is to beunderstood that the key will be of equal value where a security systemwill perform other functions such as identification of the key or theoperation of different types of mechanism.

What we claim is:

l. A key for actuating a security system having key receiving means,said key comprising a body member, a plurality of contacts mounted onsaid body member for conveying a binary coded permutation of signals tothe key receiving means, a plurality of conductor paths each of whichinterconnects at least two of said plurality of contacts to enable saidcontacts to convey a binary coded permutation of signals to the keyreceiving means of the security system, and control means disposed insaid plurality of conductor paths for controlling the conductivity ofsaid plurality of conductor paths, said control means having a firstcondition wherein the conductor paths conduct in a predetermined mannerand said contacts convey said binary coded permutation of signals to thekey receiving means and a second condition in which said conductor pathsare prevented from conducting in said predetermined manner and saidcontacts are inoperable to convey said binary coded permutation ofsignals.

2. A key for actuating a security system as defined in claim 1 whereinsaid control means is operable to render at least one of said conductivepaths, which is disposed between at least a first and second one of saidcontacts, conductive when said control means is in one of said first andsecond conditions and nonconductive when said control means is in theother of said first and second conditions, said first one of saidcontacts being operable to convey a l bit of information when saidconductive path is conductive and a 0 bit of information when saidconductive path is non-conductive, said bits of information forming apart of said binary coded permutation of signals.

3. A key for actuating a security system as defined in claim 2 whereinsaid second one of said contacts is a power receiving contact operableto have a potential applied thereto upon engagement of said powerreceiving contact with the key receiving means, said power receivingcontact transmitting said potential to said control means to therebyactuate said control means to said first condition.

4. A key for actuating a security system as defined in claim 1 furtherincluding a power receiving contact operable to have a potential appliedthereto upon engagement with said key receiving means and wherein atleast one of said plurality of contacts is operable to apply a potentialto the key receiving means upon engagement therewith when said controlmeans is in said first condition, said power receiving contact directingsaid potential to said control means to thereby actuate said controlmeans to said first condition to control the potential applied by saidone contact to the key receiving means.

5. A key for actuating a security system as defined in claim 4 wherein asecond one of said plurality of contacts is operable to have a potentialapplied thereto upon engagement with the key receiving means and a thirdone of said plurality of contacts is operable to apply a potential tothe key receiving means upon engagement therewith, said second contactdirecting said potential to said control means to thereby control thepotential applied by said third contact to the key receiving means, saidsecond contact having no potential applied thereto when said thirdcontact is utilized to convey a 0 bit of information to the keyreceiving means to actuate a security system with one predeterminedbinary coded permutation and said second contact having a potentialapplied thereto to enable said third contact to direct a 1 bit ofinformation to the key receiving means to effect actuation of a securitysystem by another predetermined binary coded permutation.

6. A key for actuating a security system as defined in claim 1 furtherincluding a power receiving contact operable to have a potential appliedthereto upon engagement with the key receiving means and wherein saidcontrol means includes switch means disposed in at least one of saidplurality of conductor paths for controlling the conductivitytherethrough, said power receiving contact being connected with saidswitch means, said switch means having a conductive condition when apotential is applied thereto by said power receiving contact and saidpower receiving contact is engaged with the key receiving means and anonconductive condition when said power receiving contacts aredisengaged from the key receiving means.

7. A key for actuating a security system as defined in claim 6 whereinsaid switch means includes a transistor having its base, collector, andemitter connected to first and second ones of said plurality of contactsand to said power receiving contact, said transistor having anonconductive state when said plurality of contacts and power receivingcontact are disengaged from the key receiving means and a conductivestate when said plurality of contacts and said power receiving contactengage with the key receiving means and a predetermined potential isapplied to said first and second of said plurality of contacts and tosaid power receiving contact, said transistor when in said conductivestate enabling said plurality of contacts to convey said binary codedpermutation of signals to the key receiving means.

8. A key for actuating a security system having a plurality of contactssome of which receive information from said key and at least one ofwhich is a power contact for applying a potential to said key, said keycomprising a body member, a plurali- I ty of spaced apart key contactsmounted on said body member, each of said plurality of key contactshaving a first end portion and a second end portion that is engageablewith the plurality of contacts of the security system for conveyinginformation to the security system to effect actuation thereof, a powerreceiving contact engageable with the power contact of the securitysystem for directing a potential to at least one of said plurality ofkey contacts, and control means mounted on said body memberinterconnecting said first end portions of at least a portion of saidplurality of key contacts, said control means having a first conditionwhen said key contacts engage with the plurality of contacts of thesecurity system and said power receiving contact engages with the powercontact and a second condition when said key contacts are disengagedfrom the plurality of contacts of the security system, said controlmeans when in said first condition interconnecting said key contacts ina predetermined manner to enable said key contacts to direct apredetermined code to the plurality of contacts of the security system,said control means when in said second condition interconnecting saidkey contacts in a second predetermined manner to prevent said keycontacts from conveying said predetermined code.

9. A key for actuating a security system as defined in claim 8 whereinsaid predetermined code directed to the security system when saidcontrol means is in said first condition is a binary coded permutation,said binary coded permutation including 0 and 1 bits of information,each of said plurality of key contacts being operable to convey a 1 bitof information when said key contacts receive a potential appliedthereto from said power receiving contact and a 0 bit of informationwhen said key contacts are prevented from having a potential appliedthereto by said power receiving contact, said control means when in saidfirst condition enabling at least one of said key contacts to have apotential applied thereto by said power receiving contact and when insaid second condition preventing a potential from being applied fromsaid power receiving contact to said one key contact.

10. A key for actuating a security system as defined in claim 8 whereinsaid power receiving contact is connected to said control means, saidpower receiving contact upon the application of a potential thereto bythe power contact actuating said control means to said first condition.

11. A key for actuating a security system as defined in claim switchmeans disposed in at least one of said plurality of conductor paths forcontrolling the conductivity therethrough,

said power receiving contact being connected with said switch means,said switch means having a conductive condition when a potential isapplied thereto by said power receiving contact and said power receivingcontact is engaged with the key receiving means and a nonconductivecondition when said power receiving contact is disengaged from the keyreceiving means.

13. A key for actuating a security system as defined in claim 12 whereinsaid predetermined code is a binary coded permutation of signals thatsaid key contacts direct to the plurality of contacts of the securitysystem, said binary coded permutation of signals being controlled by theconduction and non-conduction effected by said control means betweensaid power receiving contact and said plurality of key contacts, each ofsaid key contacts conveying a 1 bit of information when said controlmeans effects conduction between said key contact and said powerreceiving contact and a 0 bit of information when said control meansprevents conduction between said key contact and said power receivingcontact.

14. In a key for applying a particular binary coded permutation ofelectric signals to an electric security system and having a pluralityof contacts through which the signals are applied to the system, saidparticular permutation comprising a normal code of the key, circuitmeans interconnecting contacts of said plurality of contacts on the key,control means forming a part of said circuit means and changing statewhen potential is applied through a certain combination of said contactsto the circuit through portions of said circuit means through which saidpotential will act when said control means are in a changed state toestablish said particular permutation of signals the said plurality ofcontacts, and the establishing of said signal permutation through saidcontrol means circuit portions being dependent upon the changed state ofthe control means so that said control means will withhold the normalkey code when a potential is applied through a contact combination thatdiffers from said certain combination.

15. A key for applying a particular binary coded permutation of electricsignals to an electric security system as defined in claim 14 in whichsaid circuit means include portions whereby said control means make onecontact of said plurality of contacts relatively conductive andnonconductive so as to offer alternately a 1 bit signal or a 0 bitsignal.

16. A key for applying a particular binary coded permutation of electricsignals to an electric security system as defined in claim 14 in whichsaid circuit means include a portion that causes said control means tochange state in response to a potential applied through a furthercontact of said plurality of contacts.

17. A key for applying a particular binary coded permutation of electricsignals to an electric security system as defined in claim 14 in whichsaid circuit means include resistive ele- I ments offering a limiteddegree of conductivity between contacts of said plurality of contacts.

l' l l

1. A key for actuating a security system having key receiving means,said key comprising a body member, a plurality of contacts mounted onsaid body member for conveying a binary coded permutation of signals tothe key receiving means, a plurality of conductor paths each of whichinterconnects at least two of said plurality of contacts to enable saidcontacts to convey a binary coded permutation of signals to the keyreceiving means of the security system, and control means disposed insaid plurality of conductor paths for controlling the conductivity ofsaid plurality of conductor paths, said control means having a firstcondition wherein the conductor paths conduct in a predetermined mannerand said contacts convey said binary coded permutation of signals to thekey receiving means and a second condition in which said conductor pathsare prevented from conducting in said predetermined manner and saidcontacts are inoperable to convey said binary coded permutation ofsignals.
 2. A key for actuating a security system as defined in claim 1wherein said control means is operable to render at least one of saidconductive paths, which is disposed between at least a first and secondone of said contacts, conductive when said control means is in one ofsaid first and second conditions and nonconductive when said controlmeans is in the other of said first and second conditions, said firstone of said contacts being operable to convey a 1 bit of informationwhen said conductive path is conductive and a 0 bit of information whensaid conductive path is non-conductive, said bits of information forminga part of said binary coded permutation of signals.
 3. A key foractuating a security system as defined in claim 2 wherein said secondone of said contacts is a power receiving contact operable to have apotential applied thereto upon engagement of said power receivingcontact with the key receiving means, said power receiving contacttransmitting said potential to said control means to thereby actuatesaid control means to said first condition.
 4. A key for actuating asecurity system as defined in claim 1 further including a powerreceiving contact operable to have a potential applied thereto uponengagement with said key receiving means and wherein at least one ofsaid plurality of contacts is operable to apply a potential to the keyreceiving means upon engagement therewith when said control means is insaid first condition, said power receiving contact directing saidpotential to said control means to thereby actuate said control means tosaid first condition to control the potential applied by said onecontact to the key receiving means.
 5. A key for actuating a securitysystem as defined in claim 4 wherein a second one of said plurality ofcontacts is operable to have a potential applied thereto upon engagementwith the key receiving means and a third one of said plurality ofcontacts is operable to apply a potential to the key receiving meansupon engagement therewith, said second contact directing said potentialto said control means to thereby control the potential applied by saidthird contact to the key receiving means, said second contact having nopotential applied thereto when said third contact is utilized to conveya 0 bit of information to the key receiving means to actuate a securitysystem with one predetermined binary coded permutation and said secondcontact having a potential applied thereto to enable said third contactto direct a 1 bit of information to the key receiving means to effectactuation of a security system by another predetermined binary codedpermutation.
 6. A key for actuating a security system as defined inclaim 1 further including a power receiving contact operable to have apotential applied thereto upon engagement with the key receiving meansand wherein said control means includes switch means disposed in atleast one of said plurality of conductor paths for controlling theconductivity therethrough, said power receiving contact being connectedwith said switch means, said switch means having a conductive conditionwhen a potential is applied thereto by said power receiving contact andsaid power receiving contact is engaged with the key receiving means anda nonconductive condition when said power receiving contacts aredisengaged from the key receiving means.
 7. A key for actuating asecurity system as defined in claim 6 wherein said switch means includesa transistor having its base, collector, and emitter connected to firstand second ones of said plurality of contacts and tO said powerreceiving contact, said transistor having a nonconductive state whensaid plurality of contacts and power receiving contact are disengagedfrom the key receiving means and a conductive state when said pluralityof contacts and said power receiving contact engage with the keyreceiving means and a predetermined potential is applied to said firstand second of said plurality of contacts and to said power receivingcontact, said transistor when in said conductive state enabling saidplurality of contacts to convey said binary coded permutation of signalsto the key receiving means.
 8. A key for actuating a security systemhaving a plurality of contacts some of which receive information fromsaid key and at least one of which is a power contact for applying apotential to said key, said key comprising a body member, a plurality ofspaced apart key contacts mounted on said body member, each of saidplurality of key contacts having a first end portion and a second endportion that is engageable with the plurality of contacts of thesecurity system for conveying information to the security system toeffect actuation thereof, a power receiving contact engageable with thepower contact of the security system for directing a potential to atleast one of said plurality of key contacts, and control means mountedon said body member interconnecting said first end portions of at leasta portion of said plurality of key contacts, said control means having afirst condition when said key contacts engage with the plurality ofcontacts of the security system and said power receiving contact engageswith the power contact and a second condition when said key contacts aredisengaged from the plurality of contacts of the security system, saidcontrol means when in said first condition interconnecting said keycontacts in a predetermined manner to enable said key contacts to directa predetermined code to the plurality of contacts of the securitysystem, said control means when in said second condition interconnectingsaid key contacts in a second predetermined manner to prevent said keycontacts from conveying said predetermined code.
 9. A key for actuatinga security system as defined in claim 8 wherein said predetermined codedirected to the security system when said control means is in said firstcondition is a binary coded permutation, said binary coded permutationincluding 0 and 1 bits of information, each of said plurality of keycontacts being operable to convey a 1 bit of information when said keycontacts receive a potential applied thereto from said power receivingcontact and a 0 bit of information when said key contacts are preventedfrom having a potential applied thereto by said power receiving contact,said control means when in said first condition enabling at least one ofsaid key contacts to have a potential applied thereto by said powerreceiving contact and when in said second condition preventing apotential from being applied from said power receiving contact to saidone key contact.
 10. A key for actuating a security system as defined inclaim 8 wherein said power receiving contact is connected to saidcontrol means, said power receiving contact upon the application of apotential thereto by the power contact actuating said control means tosaid first condition.
 11. A key for actuating a security system asdefined in claim 10 wherein said power receiving contact directs saidpotential to said control means to thereby control the potential appliedby other of said key contacts to the plurality of contacts of thesecurity system.
 12. A key for actuating a security system as defined inclaim 8 further including a power receiving contact operable to have apotential applied thereto upon engagement with the key receiving means,and wherein said control means includes switch means disposed in atleast one of said plurality of conductor paths for controlling theconductivity therethrough, said power receiving contact being connEctedwith said switch means, said switch means having a conductive conditionwhen a potential is applied thereto by said power receiving contact andsaid power receiving contact is engaged with the key receiving means anda nonconductive condition when said power receiving contact isdisengaged from the key receiving means.
 13. A key for actuating asecurity system as defined in claim 12 wherein said predetermined codeis a binary coded permutation of signals that said key contacts directto the plurality of contacts of the security system, said binary codedpermutation of signals being controlled by the conduction andnon-conduction effected by said control means between said powerreceiving contact and said plurality of key contacts, each of said keycontacts conveying a 1 bit of information when said control meanseffects conduction between said key contact and said power receivingcontact and a o bit of information when said control means preventsconduction between said key contact and said power receiving contact.14. In a key for applying a particular binary coded permutation ofelectric signals to an electric security system and having a pluralityof contacts through which the signals are applied to the system, saidparticular permutation comprising a normal code of the key, circuitmeans interconnecting contacts of said plurality of contacts on the key,control means forming a part of said circuit means and changing statewhen potential is applied through a certain combination of said contactsto the circuit through portions of said circuit means through which saidpotential will act when said control means are in a changed state toestablish said particular permutation of signals the said plurality ofcontacts, and the establishing of said signal permutation through saidcontrol means circuit portions being dependent upon the changed state ofthe control means so that said control means will withhold the normalkey code when a potential is applied through a contact combination thatdiffers from said certain combination.
 15. A key for applying aparticular binary coded permutation of electric signals to an electricsecurity system as defined in claim 14 in which said circuit meansinclude portions whereby said control means make one contact of saidplurality of contacts relatively conductive and nonconductive so as tooffer alternately a 1 bit signal or a 0 bit signal.
 16. A key forapplying a particular binary coded permutation of electric signals to anelectric security system as defined in claim 14 in which said circuitmeans include a portion that causes said control means to change statein response to a potential applied through a further contact of saidplurality of contacts.
 17. A key for applying a particular binary codedpermutation of electric signals to an electric security system asdefined in claim 14 in which said circuit means include resistiveelements offering a limited degree of conductivity between contacts ofsaid plurality of contacts.